If you want to get hired by an investment bank in Hong Kong, you need one key skill on your resume – Mandarin.

In a change of strategy from only a few years ago, investment banks want top graduates who can speak the same language as clients in Mainland China. This means that Hong Kongers – who usually have Cantonese as their first language – are being frozen out of the job market.

We spoke to a few new analysts in HK. One estimates that around 80% of each class are Mainlanders. A lot of them don’t speak Cantonese at all. “This is to do with clients. We are here to serve mainland clients,” says one analyst who joined a major US bank in HK after leaving university in the UK. “Sometimes we even prepare pitch books in Chinese.”

Jimmy Liu, a first-year analyst at Credit Suisse HK, thinks the specific ratio depends on teams. “For some banks the China team is huge, and industry teams also need some native Mandarin speakers as China business is much larger than other regions’,” he says. As far as he knows, at least 60% are native Mandarin speakers in each class.

These new recruits are not just being recruited for their language skills. Most attend elite universities in either the US or Europe, usually a finance related subject, and then return to China to enter the job market. The number of Chinese students studying overseas has quadrupled from 100,000 to 400,000 over the past decade. Hong Kong is an obvious choice to kick-start their banking career.

There are good reasons for recruiting Mandarin speakers. Hong Kong is the de facto choice for Chinese companies wishing to go overseas. In the past decade almost all heavyweight Chinese state-owned enterprises have been listed on the Hong Kong Stock Exchange. Others in the process of expansion have received advice from banks in Hong Kong.

Nonetheless, this has the potential to create tensions. Another analyst claims to have seen headhunters crossing out potential candidates whose surnames don’t read like a Mainland one. “I doubt whether this amounts to discrimination,” he says in an unsure tone. “But certainly we are seeing more and more Mainlanders here.”

This doesn’t mean Hong Kongers are completely squeezed out, though. “there are quotas for Mandarin speakers and quotas for non-Mandarin speakers,” Liu points out. “Hong Kongers go to non- quota, but still have an advantage over candidates from other regions because they read and write in Chinese.”

So, where have the local Hong Kongers gone to? “More in the middle and back office, where roles are less client-facing,” suggests one Mainland analyst. “We are hired because we need to deal with mainland clients face-to-face, but non-front-office roles require much less of that.”

Rachel Liu, a Singapore-based associate director at headhunters Profile Search & Selection, says that her firm is increasingly hearing from local Hong Kong financial professionals enquiring about relocating to Singapore, which is still largely an ethnic-Chinese society but requires much less Mandarin-speaking ability (although it’s on the rise too).

On the other hand, many Hong Kongers who have learnt Mandarin have already headed north to live and work in major Chinese cities such as Beijing, Shanghai and Shenzhen. “Many of them have joined China’s private equity firms,” says one analyst. “Mandarin is a must-have skill if you want to do PE there.”